Polymeric products deactivate carbon-based catalysts in catalytic oxidation reactions

A gap in understanding the deactivation mechanisms underlying heterogeneous catalytic advanced oxidation processes (HG-AOPs) constrains their sustainable development. This study clarifies the linkage between polymerization phenomena and catalyst deactivation in HG-AOPs employing carbon materials. We demonstrate that the deposition of polymerization products leads to a self-inhibition effect by maintaining a consistent polymerization energy barrier, regardless of the increasing degree of polymerization (DP). This consistency facilitates the persistent formation of high-DP products. Using machine learning analysis, we reveal that higher DPs intensify hydrophobic interactions and van der Waals forces, which promote the robust adhesion of polymeric products to the catalyst surface. These adherent layers compete with oxidants for active sites, impeding oxidant adsorption, obstructing electron transfer and ultimately hindering further catalytic activity. Additionally, we evaluate several catalyst-regeneration methods from a sustainability standpoint. This work contributes to developing sustainable strategies for effectively utilizing carbon-based nanomaterials in water treatment, offering a foundation for future innovation in HG-AOPs. Catalyst deactivation commonly occurs in heterogeneous catalytic advanced oxidation processes, but the mechanisms are not well understood. This study finds that catalyst deactivation is closely related to deposition of polymeric products of the pollutant-removal process.